Method of manufacturing tape reels



g- 3, 1967 A. c. cuvA 3,334,402

METHOD OF MANUFACTURING TAPE HEELS Original Filed Aug. 16, 196.3

INVENTOR.

ANGELO C. CUVA ATTORNEY United States Patent 3,334,402 METHOD OF MANUFACTURING TAPE REELS Angelo C. Cuva, Santa Clara, Calif. (1024 Sumac Drive, Sunnyvale, Calif. 94086) Original application Aug. 16, 1963, Ser. No. 302,547, now

Patent No. 3,232,550, dated Feb. 1, 1966. Divided and this application Oct. 22, 1965, Ser. No. 509,469

8 Claims. (Ci. 29-159) This application is a divisional application of my copending application Ser. No. 302,547, filed Aug. 16, 1963, entitled, Tape Reel, now Patent No. 3,232,550, granted on Feb. 1, 1966.

This invention relates to precision reels and more particularly to an improvement in the method of manufacture of a precision reel for the storage of magnetic tape.

Magnetic recording and reproducing devices widely employed in the computer, data processing and entertainment fields utilize very long narrow magnetically coated strips of material upon which suitable signals are recorded. Such strips are commonly known as magnetic tape.

Long strips of magnetic tape are most efficiently stored by being rolled or wound in layers around the hub of a tape reel. When recording information upon the tape or reproducing the information previously recorded on the tape, the usual procedure is to mount a supply reel of tape upon a drive shaft, thread the tape past a recording and/or reproducing transducer, and attach the beginning of the tape to a second reel called a take-up reel. By means of a tape drive mechanism clamping the tape, the tape is driven at a selected speed past the transducer and the reels respectively supply and take-up the tape at varying angular speeds such that the tape remains taut at all times regardless of the amount of tape on either reel.

The tape reels are very frequently subjected to extremely rapid starting and stopping speeds, requiring that they be accurately balanced and be very rigidly constructed. The parts comprising the reel must be maintained in proper operating relationship with each other in spite of rough handling, high acceleration and deceleration forces during use of the reel.

Flanges or outer discs of a reel must be maintained in a parallel relationship with each other in order to prevent wobble or lateral movement of the flanges during rotation of the reel. Wobbling flanges may scrape against the edges of the tape being wound upon or off of a reel and thereby seriously slow down or seriously damage the tape or the tape deck. In fact, rigid specifications of tape reels have been set down such as, for example, military specification MIL-R-22842 '(SHIPS) and supplements imposing very rigid requirements on lateral runout and other dimensions.

Since a reel must be started and stopped within very short periods of time it is necessary that the rotational inertia of a reel be kept at a minimum value. Low rotational inertia of the reel permits a small motive power to bring it up to full operating speed in the required short period of time and permits a small braking power to be used to bring the reel to a stop in the required short period of time.

Aluminum has been found to meet the inertia and strength requirement of magnetic tape reels. However, a serious problem has been encountered when aluminum reel parts such as hubs and flanges are fastened together by means of fasteners such as screws, rivets, nuts, bolts and washers that are made of ametal other than aluminum, such as, for example, high strength steel.

The problem encountered is that of chemical or electrolytic action between the steel fastener and the aluminum parts in contact with the fastener. In addition corrosion of the steel fastener itself by contamination in the atmosphere creates serious problems. Electrolytic action between dissimilar metals, or metal oxide which is usually present to some extent on the surface of all metals and invariably present on the surface of aluminum causes corrosion at the interfaces of the two dissimilar metals.

Corrosion at the interfaces frequently causes a loosening of the fastener thereby destroying the rigid attach-ment of the parts of the reel to one another resulting in loose flanges destroying flange parallelism and producing runout. Aluminum itself is, however, normally not corroded by the usual atmospheric environment in which tape reels are operated. It has heretofore not been found possible to utilize aluminum screws, bolts, or nuts as fasteners of the reel parts since the tensile strength of aluminum is not suflicient to pass the tests imposed by applicable performance and environmental specifications.

It is therefore an object of this invention to provide an improved method of manufacture for a tape reel.

It is a further object of this invention to provide method of rigidly securing the flanges to the hub of a precision tape reel without subjecting either the flanges or the hub to stresses and which is ideally suited for the employment of corrosion-resistive fastening means.

It is a still further object of this invention to provide for an easily and economically manufactured tape reel.

Another object of this invention is to provide an improved method of fastening aluminum parts together with aluminum fasteners.

Further objects and advantages of the present invention will become apparent to those skilled in the art to which the invention pertains as the ensuing description proceeds.

The stated objects are realized, according to the present invention, by utilizing a press fit, either directly or indirectly, to fasten the flanges to the hub Without use of dissimilar metals. In one embodiment of this invention an oversized rivet-shaped fastener of the same material as the flanges and the hub is shrunk by freezing and inserted into aligned fastener openings in the hub and flanges. As the cooled and contracted fastener subsequently warms to ambient temperature, it expands to its original size to firmly grip the peripheral surface of the fastener openings in the hub and to thereby hold the flanges firmly to the hub. Since the fastener is comprised of the same material as the hub and flanges, it is chemically and electrolytically neutral with respect thereto and no electrolytic action takes place to weaken the bond.

In another embodiment of this invention the bond between the flanges and the hub is produced directly by press fitting the flanges, constructed with a tapered guiding surface, upon the shoulders of the hub and thereafter securing the flanges to the hub by a cementitious material.

The features of novelty that are considered characteristic of this invention are set forth with particularity in the appended claims. The organization and method of operation of the invention itself will best be understood from the following description when read in connection with the accompanying drawing in which:

FIGURE 1 is a perspective view of one embodiment of the tape reel of the present invention;

FIGURE 2 is a cross sectional view of the tape reel of FIG. 1 taken along line 2-2;

FIGURE 3 is a cross sectional view, similar to that of FIG. 2, of another embodiment of the tape reel of the present invention; and

FIGURE .4 is an enlarged fractional cross sectional view of the encircled portion of FIG. 3 marked 4.

Reference to FIG. 1 shows a spool or reel 10 which is comprised of a pair of flanges or circular discs 11 and 12 spaced apart from each other by attachment, at opposite ends, to a cylindrically shaped hub 13. Each disc 11 and 12 is provided with a circular cutout centered therein. Each disc is comprised of a material having a high strength to weight ratio; for example aluminum or magnesium. Since reel is to be rotated at high speed about an axis passing through the center of and normal to each of discs 11 and 12. The rotational inertia of reel 10 may be reduced considerably, without greatly reducing its strength, by removing portions of disc material from near the outer periphery. Such inertia reduction is shown in FIG. 1 as cutouts 14 provided in discs 11 and 12. Cutouts 14 also provide finger access to hub 13 for beginning winding of a length of tape on reel 10 about hub 13.

The inner peripheral surface of hub 13 may be provided with mounting grooves 15 adapted to removably engage a drive shaft of a reel engaging apparatus (not shown) such as a tape deck.

As best seen in FIG. 2, hub 13 is provideed with annular outwardly depending mounting bosses 16 and 17 at each end thereof. Disc 11 is mounted on hub 13 by positioning the circular cutout of the disc over mounting boss 16 and against one end face of hub 13. Likewise, disc 12 is mounted on hub 13 by positioning the circular cutout of the disc over mounting boss 17 and against the other end face of hub 13. Circular flanges 11 and 12 are thus centered about the axis of hub 13 and are positioned substantially parallel with respect to each other.

There will now be described, with reference to FIG. 2, the improved method and structural details of maintaining the discs 11 and 12 in rigid relationship with hub 13 and in parallel relationship with each other. Each end face of hub 13 outside of bosses 16 and 17 is provided with a series of cylindrical bores 18 and 19 respectively which extend through hub 13. Each bore is preferably parallel to the axis of rotation of reel 10 and on a common pitch diameter. Each series of bores is angularly displaced with respect to the other so that since they extend through hub 13, each end face shows twice as many openings as there are bores in one series. Flange 11 is also provided with a series of countersunk openings 20, which are aligned with corresponding ones of bores 18 when mounted over a boss 16 and properly positioned. Flange 12 is likewise provided with a series of counter sunk openings 21 aligned with bores 19.

Individual fasteners 23 are inserted into each pair of aligned openings and bores 18 so that its head portion engages the flange and its shank portion engages the bore. Each fastener 23, by securely gripping the peripheral surface of a bore by dilation, rigidly secures the flanges permanently to hub 13 and parallel to one another. Fasteners 23, utilized in the illustrated embodiment of the present invention, are comprised of a material that is chemically and electrolytically neutral with respect to the material of which hub 13 and discs 11 and 12 are comprised. The preferred material for fastener 19 is the same as the material of hub 13 and discs 11 and 12.

A suitable fastener 23 includes a cylindrical shank portion and a sloped head portion continuous with the shank portion. Fastener 23 is thus shaped similar to a countersunk head rivet. The diameter of the shank portion, at ambient or room temperature, is carefully selected to be somewhat greater than the diameter of bores 18 and 19. Thus a fastener 23 cannot be inserted into a pair of aligned bores and openings when hub 13, discs 11 and 12 and fastener 23 are all at the same ambient temperature.

In order that a fastener 23 may be inserted into a pair of aligned bores and openings, the diameter of the fastener 23 is temporarily reduced to a value not greater than the diameter of the bores 18 and 19.

This is most easily accomplished by lowering the temperature of fastener 23 to a value sufliciently low so that the material comprising the fastener 23 contracts to reduce the diameter of the shank and head until it fits into bores 18 and 19.

One method of cooling the fastener 23 is by immersion into liquid nitrogen which is typically maintained at aboiling temperature of minus 100 F. Such contraction permits easy insertion of fastener 23 into a pair of aligned bores and openings. If desired, cooled fastener 23 may be inserted with the aid of steady pressure applied by a pressing fixture.

Upon heating up to ambient temperature, fastener 23 expands or dilates tightly against and firmly grips the walls of the bore. Thus the fastener 23 firmly maintains the discs 11 and 12 in proper operating relationship with hub 13 and parallel with each other.

Since fasteners 23 are made of the same material as discs 11 and 12 and hub 13, there will be no electrolytic action to cause corrosion. Since aluminum itself is usually completely protected by a very thin film of aluminum oxide, the surfaces of fastener 19 are protected from corrosion.

The method heretofore described for fastening parts together has other advantages. Simple drilling of bores and openings in a part is more economical than providing a threaded opening such as would be required if conventional screws were utilized. In addition, there is no hammering required such as would be the case with simple rivets, to cause the fasteners to grip the discs 11 and 12 and hub 13, thereby assuring that the parts are not unbalanced or damaged during assembly.

There is illustrated in FIGS. 3 and 4 another form of the present invention wherein a pair of flanges 30 and 31 are secured to a hub 32 without the use of screws, bolts, nuts, or rivets. Each end face of hub 32 is provided with a boss 33 and 34 having a tapered shoulder 35 immediately adjacent to the end face as best seen in FIG. 4. A circumferential shallow groove 36 is provided in each end face of hub 32 for receiving a fastener material 37.

The central opening of flanges 30 and 31 is provided with a tapered shoulder 38 which conforms to either boss 33 and 34 of the hub 31 when mounted thereon and the cylindrical portion of the central opening is dimensioned for press-fitting upon the boss. Flanges 30 and 31 are also provided with a circumferential groove 38 which is in alignment with groove 36 when the flange is press-fitted upon the mounting boss. In this manner grooves 36 and 38 are opposite to one another and provide a closed channel which is filled with fastening material 37.

On assembling flanges 30 and 31 on hub 32, grooves 36 and 38 are filled with a material 37 which upon drying or heating will firmly bond to the surfaces of the grooves and thereby secure the parts together. Thereafter, each flange is press-fitted upon its mounting boss, the tapered portion providing alignment means. A typical fastener material 37 may be, for example, a thermosetting nylon-epoxy adhesive which may be cured while applying approximately 25 pounds per square inch pressure to the adjacent parts while maintaining the adhesive material 37 and parts at approximately 350 F. for about one hour.

The flanges may be press-fitted over the mounting bosses by means of a suitable steady pressure applying fixture. Such a pressure applying fixture will press the flange firmly upon the mounting boss and urge the tapered shoulder of the flange into engagement with the tapered shoulder of the mounting boss for good alignment. It has been found that a taper of about 20 degrees from the axis of flange 31 and occupying a portion of about one-third the thickness of the flange is eminently suitable to achieve a good press fit and proper alignment of parts.

The embodiment of the present invention described and illustrated in FIG. 3 has the advantage that no metal fasteners are utilized. Grooves 36 and 39 are shown respectively on the end face of hub 32 and a side of flange 31 since such locations are more easily machined. The adjacent grooves for receiving the fastening material may be provided at other suitabale locations such as the tapered shoulders if desired.

While the principles of the invention have been made clear in the illustrative embodiments, there will be obvious to those skilled in the art, many modifications in structure, arrangement, proportions, the elements, materials, and components, used in the practice of the invention, and otherwise, which are adapted for specific encooling the fasteners to said selected temperature; and vironments and operating requirements, without departinserting the cooled fasteners through the openings in ing from these principles. The appended claims are therethe flanges into the bores in the hub so that, upon fore intended to cover and embrace any such modificawarming to the environmental temperature, the tiOIlS Within the limits only Of the true spirit and scope 5 smooth-surfaced body portion of the fasteners grip of the invention. the smooth-walled bores of the hub by dilation.

What is claimed is: 5. The method of securing a lightweight, corrosion- The method of manufacturing a p reel having a resistive, metallic tape reel flange to the annular endface hub and a pair of flanges comprising the steps of: of a lightweight, corrosion-resistive, metallic tape reel hub providing a series of axially extending, substantially 10 comprising th teps f;

smooth bores in each annular end face of the hub; roviding the annular end face of the tape reel hub providing a series of openings in each flange arranged with a plurality of bores;

to align with said bores; providing the tape reel flange with a plurality of openproviding fasteners having head portions and shank porings arranged in registry with the bores in the hub; tions Whose diameter is greater than the diameter of providing a plurality of metallic fasteners which are said bores; electrically neutral with respect to the flange and hub temporarily reducing the diameter of the shank portion and which have head portions larger than the openof said fasteners While inserting said fasteners ings in the flange and temperature contractible body through the openings in said flanges into the aligned portions whose diameters are greater than the diambores so that the head portion bears against the eter of the bores at the normal environment temperafiehges; and ture in which the tape reel operates and smaller than enlarging the diameter of the shank portions to thei the diameter of the bores when cool-ed to :a selected Original Size 50 that the fasteners p the Peripheral temperature below the normal environmental temsurfaces of the bores by dilation. perature; 2. The method of securing a tape reel flange to the contracting the fasteners by cooling to at least the seannular end face of a tape reel hub comprising the steps lected temperature; and f: inserting the contracted fasteners through the openings P Ovidhlg the annular end face of the p feel hub in the flanges into the bores in the hub so that, upon with a plurality of bores; warming to the normal environmental temperature, providing the p reel flange i a p ur i y f p nthe body portion of the fasteners expand to grip the ings arranged in registry with the bores in the hub; b providing a plurality of fasteners having head p n 6. The method of securing a lightweight, corrosion- Whieh are larger than the Openings in the flange and resistive, metallic tape reel flange to the annular end face eohttaetihle y Portions Whose diameters in the of a lightweight, corrosion-resistive, metallic tape reel hub uncontracted state are greater than the diameter of comprising th steps of: the bores and in the contracted state are smaller than idi th nular end face of the tape reel hub with the diameter of the bores; a plurality of bores; Contracting the fastehere; and providing the tape reel flange with a plurality of openinserting the contracted fasteners through the openings i arranged i r gistry with the bores in the hub;

in the flanges into the bores in the huh 80 that, p providing a plurality of metallic fasteners which are dilation t0 the uncontraeted State, the y F U011 0t electrolytically neutral with respect to the flanges and the fasteners grip the bores. hub, and which are maintained at a temperature be- The method of Securing a p l'eel flange t0 the low the normal environmental temperature at which nular end face of a tape reel hub comprising the steps of: th tape reel o erate said fasteners having head providing the annular end face of the tape reel hub with portions which are larger than the openings in the a plurality of bores; flange and body portions whose diameters are smaller providing the tape reel flange with a plurality of openthan the diameter of the bores at the maintained temihgs arranged in registry With the bores in the perature and which expand to diameters larger than Providing a plurality of fasteners having head Portions the diameter of the bores at the normal environwhich are larger than the openings in the flange and t l temperature; expandable y Portions Whose diameters in the inserting the fasteners through the openings in the expanded state are greater than the diameter of the flanges i t the bore in the hub; and bores and in the non-expanded state are smaller than expanding th fasteners by allowing th t warm up the ia f the bores; to the normal environmental temperature in which inserting the fasteners in the non-expanded state the tape reel operates, so that, upon expansion, the through the openings in the flanges into the bores in body portions of the fasteners tightly grip the bores. the hub; and 7. The method of securing a tape reel flange, conexpanding the fasteners t0 the expanded State, 80 that, structed of a first, lightweight, corrosion-resistive metal, to 1113011 expansion, the y Portions of the fasteners the annular end face of a tape reel hub, constructed of a p the hOTeS- second, lightweight, corrosion-resistive metal, comprising 4. The method of securing a tape reel flange to the the steps annular end face of a tape reel hub comprising the steps providing the annular end .f of h t l h b with providing the annular end face of the tape reel hub with a plurality of axially extending, cylindrical, smooth-walled bores;

providing the tape reel flange with a plurality of openings arranged in registry with the bores in the hub;

providing a plurality of fasteners having head portions which are larger than the openings in the flange and a plurality of axially extending, cylindrical, smoothwalled 'bores; providing the tape reel flange with a plurality of openings arranged in registry with the bores in the hub; providing a plurality of fasteners, constructed of a metal electrolytically neutral with respect to said first and second metal, having head portions which are larger having cylindrical, smooth-surfaced body portions than the p nings in the flange and cylindrical, whose diameters are greater than the diameter of the smooth-surfaced h y Portlehs Whose t rs ar bores at the normal environmental temperature and greater than the dlametel 0f the I S at the normal smaller than the diameter of the bores at a selected vir n ntal t mperature and smaller than the temperature which is lower than the normal environdiameter of the bores at a selected temperature whlch mental temperature; is lower than the normal environmental temperature;

cooling the fasteners to at least said selected temperature; and

inserting the cooled fasteners through the openings in the flanges into the bores in the hub so that, upon warming to the environmental temperature, the smooth-surfaced body portion of the fasteners grip the smooth-walled =bores of the hub byv dilation.

8. The method of manufacturing a tape reel having a hub and a pair of flanges comprising the steps of:

providing a series of axially extending, substantially smooth bores in each annular end face of the hub;

providing a series of openings in each flange arranged to align with said bores;

providing fasteners having head portions and having shank portions Whose diameters are greater than the diameters of said bores;

cooling the fasteners to a temperature at which the diameter of their shank portions are reduced to less than the diameters of the bores and inserting said fasteners through the openings in said flanges into the References Cited UNITED STATES PATENTS Anderson 24277.4 Mossberg 29159 Paulsen 29447 Black et al. 29447 Perlini 24271.8

JOHN F. CAMPBELL, Primary Examiner.

THOMAS H. EAGER, Examiner. 

1. THE METHOD OF MANUFACTURING A TAPE REEL HAVING A HUB AND A PAIR OF FLANGES COMPRISING THE STEPS OF: PROVIDING A SERIES OF AXIALLY EXTENDING, SUBSTANTIALLY SMOOTH BORES IN EACH ANNULAR END FACE OF THE HUB; PROVIDING A SERIES OF OPENINGS IN EACH FLANGE ARRANGED TO ALIGN WITH SAID BORES; PROVIDING FASTENERS HAVING HEAD PORTIONS AND SHANK PORTIONS WHOSE DIAMETER IS GREATER THAN THE DIAMETER OF SAID BORES; TEMPORARILY REDUCING THE DIAMETER OF THE SHANK PORTION OF SAID FASTENERS WHILE INSERTING SAID FASTENERS THROUGH THE OPENINGS IN SAID FLANGES INTO THE ALIGNED BORES SO THAT THE HEAD PORTION BEARS AGAINST THE FLANGES; AND ENLARGING THE DIAMETER OF THE SHANK PORTIONS TO THEIR ORIGINAL SIZE SO THAT THE FASTENERS GRIP THE PERIPHERAL SURFACES OF THE BORES BY DILATION. 